The present invention relates to pipe joints or pipe fittings and in particular is a pipe fitting for joining one or more plastic pipes by a fusing operation.
Pipe joints or fittings adapted for joining plastic pipes, such as polyethylene pipes, are well known in the art and typically include, one or more socket portions for receiving the pipes to be joined, and an annular projection internal to the pipe fitting for serving as a stop for the joined pipes. Also, the internal diameter of the socket is typically slightly smaller than the external diameter of the resin pipes to be joined thereto for the purpose of insuring a tight fit. Pipes are joined to pipe fittings in the following conventional manner. The outer peripheral part of the pipe to be later inserted into the fitting socket and the inner peripheral part of the fitting socket are made molten by a conventional fusing operation. While molten, the pipe is inserted into the socket.
One of the problems associated with prior art pipe fittings of the latter type is related to the occurrence of a certain amount of molten resin overflowing during the fusing operation. Molten resin which overflows internally often collect near or on the annular projection thereby providing an additional projection in the path of the fluid for which the pipe is designed. As a result, the projection may interfere with the desired flow of the fluid through the joined pipes. Additionally, molten resin overflowing on the external portion of the joined arrangement often collects on the pipe just at the outside of the socket. The latter resin creates an unpleasant appearing surface which may also be the cause of the joined portion being broken. For example, the raised edge formed by the overflowed resin can have external forces applied thereto.